Citric Acid Cycle (Unit 2) Flashcards
What is the purpose of these enzyme-catalyzed reactions?
They together result in the oxidation of acetyl groups to CO2 and the synthesis of ATP, NADH, and FADH2.
How many enzyme-catalyzed reactions are involved
There are 8 enzyme-catalyzed reactions (8 in the mitochondrial matrix, one binds to the matrix side of the inner mitochondrial membrane).
What are the products of one acetyl-CoA in this process?
One acetyl-CoA produces 3 NADH, 1 FADH2, and 1 ATP (created through substrate-level phosphorylation).
What happens to the carbon atoms in the complete cycle?
One 2-carbon acetyl unit is consumed, and 2 CO2 are released, completing the conversion of the carbons originally in glucose to CO2.
What is the process flow starting from glucose?
1 glucose molecule produces 2 pyruvate molecules, which are then converted to 2 acetyl groups during pyruvate oxidation. All reactants are doubled.
What happens to the CoA molecule after it carries an acetyl group to the cycle?
The CoA molecule is released and participates in pyruvate oxidation to carry another acetyl group.
How does the cycle contribute to the complete oxidation of glucose?
The cycle ensures that all carbons from the original glucose molecule are fully oxidized to CO2.
How do two acetyl-CoA molecules enter the citric acid cycle?
They enter from glycolysis and the pyruvate oxidation of a glucose molecule.
What happens in step one of the citric acid cycle?
The acetyl group enters the cycle, reacting with oxaloacetate to form citrate.
What occurs in steps three, four, five, six, and eight of the citric acid cycle?
Some released energy is captured to create NADH, ATP, and FADH2.
During which steps is NAD+ reduced to NADH?
NAD+ is reduced to NADH in steps three, four, and eight.
What happens in step five of the citric acid cycle?
ATP is produced from ADP and Pi through substrate-level phosphorylation.
What occurs in step six of the citric acid cycle?
FAD is reduced to create FADH2.
How many turns of the citric acid cycle occur per glucose molecule?
There are two turns of the citric acid cycle per glucose molecule, since it creates two pyruvate molecules.
What happens to the original carbon and oxygen atoms in glucose?
They are now in CO2 and released as waste.
